Power punch press feed rolls are well known and commonly employed to feed punch presses when coils or rolls of continuous strip metal are used for feeding the dies of such presses. Automatic roll feed mechanisms are particularly advantageous in high speed automatic power press operations. In punch press feeds, it is also essential at times that the stock being fed to the punch press be released from the feed as the dies of the press contact the stock. Most dies have piloting arrangements which require that the stock be relatively free to adjust itself as the dies stamp their product.
The release of the stock being fed to the punch press from the feed rolls need be only of short duration to permit the strip locating pins or piloting pins in the die mechanism to engage the work piece and accurately locate the same, relative to the die mechanism. Generally, after the die has performed its function, the feed rolls should again be caused to grip the work strip to feed the next segment to the dies.
In addition, the intricate coordination between the feed roll mechanism and the punch press itself require expert technicians to adjust and set the feed roll mechanism on a punch press. During this adjustment, possible die damage could result if the feed setting is inaccurate.
Many prior feed roll mechanisms for punch presses contained clutches and brakes, which did not permit positive drive between the punch press components and the feed roll mechanism. Without positive drive, the punch press feed roll mechanism would get out of time with the press. As the speed was varied, clutches wore or brakes failed causing spoilage of pieces and damage to tooling.